how can I 220 v ac to 14or 25 dc without transformer?

I'm very new to this area. there is many chip dc-dc and 25 to 0-6 volt down converter.

but why there is no 220 v to 25 volt chip?? I don't understand...

Should I must use transformer??

I want very tiny converter. I want not using transformer or big condenser at all.

Can you help me?

Thanks

Oh I try to use "

TPS53355

http://www.ti.com/docs/prod/folders/print/tps53355.html

Thanks!! I need help! :)